Clamshell pressure vessel

ABSTRACT

A generally ellipsoidal pressure vessel having first and second vessel shell portions each with a thin wall lying generally along one-half of an ellipsoid and wherein one of the shell portions is supported in a fixed position and the other shell portion is supported for movement between a closed chamber position in which the shell portions cooperate in forming a sealed pressure vessel and an open chamber position in which insertion and removal of a toroidal object into and from the pressure vessel is accommodated.

Morgan Jan. 7, 1975 CLAMSHELL PRESSURE VESSEL 3,752,726 8/1973 Barefoot t. 156/96 X [75] Inventor: Harvey E. Morgan, Salisbury, N.C.

I Primary ExaminerMorris O. Wolk [73] Assigneec Brad Ragan, lnc., Spruce Pine, N.C. Assistant Emmine, ROger phiui [22] Filed; Jan. 22, 3 grtgrgey, Agent, or Firm-Parrott, Bell, Seltzer, Park 1 son [21] Appl. No.: 325,375

52 US Cl 23 290 394 2 4 [57] ABSTRACT I I 156/ 4 3 21 A generally ellipsoidal pressure vessel having first and [51] Int Cl Bolj 3/00 B2911 17/36 second vessel shell portions each with a thin wall lying [58] Field H 23/290. generally along one-half of an ellipsoid and wherein one of the shell portions is supported in a fixed posi- 32 35 tion and the other shell portion is supported for movement between a closed chamber position in which the [56] References Cited shell portions cooperate in forming a sealed pressure vessel and an open chamber position in which inser- UNITED STATES PATENTS tion and removal of a toroidal object into and from 1,688,570 Williams the pressure vessel is accommodated 1,887,250 11/1932 Stricklen et al 425/47 3,136,007 6/1964 Maher et al 21/98 UX 10 Claims, 6 Drawing Figures 1- 235} 2 1 Y W I 24 32 l l l l ea 1 viii 45 CLAMSI-IELL PRESSURE VESSEL Automotive vehicle tire renewing or rebuilding techniques which employ pressure vessels to cure elastomeric materials have come into increasing use in recent years, due to the development of techniques which do not require the use of molds. One such process is described in U.S. Pat. No. 3,464,874 issued Sept. 2, 1969, and assigned in common with the present invention. A somewhat related development has been a concurrent increase in the sizes of tires used and the increasing range of variations in tire sizes. While known pressure vessels have facilitated the accommodation of the increasing ranges of sizes of tires, difficulty is being encountered now in accommodating the very largest tires which are presently in use.

In particular, pressure vessels heretofore employed have been of generally cylindrical or drum-like configuration, having domed end closures. Such pressure vessels, as mentioned briefly in the paragraph beginning at Column 4, line 69 of U.S. Pat. No. 3,464,874, may be constructed and operated disclosed in U.S. Pat. No. 2,271,855 issued Feb. 3, 1942. Access to the interior of the pressure vessel for insertion and removal of tires into and from the pressure vessel has been made possible by hingedly mounting one of the dome end walls of the cylindrical pressure vessel. As so arranged, one portion of the pressure vessel shell has a generally cylindrical body and defines an open mouth in the form of a circle corresponding to the major diameter of the vessel. The other portion of the vessel shell is a domed end wall or closure member capable of mating with the circular open mouth of the main body of the vessel.

Such pressure vessels, while adequate for providing the temperature and pressure conditions required for the processes which have come into commercial use, present difficulties during transport and installation. In particular, the bulk of the pressure vessel required to accommodate the large tire sizes which have come into use is such that the vessel cannot easily be transported and installed. This is true even where special permits can be obtained for transporting unusually large objects, due to the limitations imposed by the dimensions of tunnels. underpasses and the like along any given routing.

In view of the above, it is an object of this invention to minimize the bulk of a pressure vessel designed to receive toroidal objects such as tire carcasses while maximizing the dimensions of the toroidal objects receivable therewithin. In accomplishing this object of the present invention, a pressure vessel is constructed to have two shell portions each having a thin wall lying generally along one-half of an ellipsoid and defining an open mouth lying generally on a plane dividing the ellipsoid on a minor axis. By dividing the pressure vessel on a minor axis of an ellipsoid, the overall dimensions of each of the shell portions is minimized so as to bring the bulk ofeach portion within the limitations imposed by the need to transport and erect the pressure vessel. Insertion and removal ofa toroidal object such as a tire carcass into and from the pressure vessel is facilitated by supporting one of the shell portions in a fixed position with the open mouth thereof disposed generally in a vertical plane and supporting the other of the shell portions for movement between a closed chamber position in which the open mouths of the shell portions abut and an open chamber position in which the mouth of the other shell portion is withdrawn.

Some of the objects of the invention having been stated, other objects will appear as the described proceeds, when taken in connection with the accompanying drawings, in which:

FIG. 1 is a plan view of a pressure vessel in accordance with this invention;

FIG. 2 is an elevation view, partially in section, taken generally along the line 2-2 in FIG. 1;

FIG. 3 is an elarged elevation view, partially in sec tion, illustrating locks mounted on one of the shell portions of the pressure vessel for securing the shell portions in closed chamber position;

FIG. 4 is an elevation view of the pressure vessel;

FIG. 5 is an enlarged perspective view ofa portion of the pressure vessel, taken generally as indicated by the arrow 5 in FIG. 2; and

FIG. 6 is a plan view of the portion of the pressure vessel illustrated in FIG. 5.

The accompanying drawings and the description which follows set forth the best mode presently contemplated for this invention. However, it is to be understood at the outset that the drawings and the description are intended as illustrations only, for the purposes of broadly teaching the present invention. With this illustrative nature of the drawings and description in mind, it is to be understood that the drawings and description are not to be limiting upon the present invention, which is contemplated as having a broad scope of utility.

The pressure vessel generally indicated at 10 in the accompanying drawings is characterized in the following description as being generally ellipsoidal. The term ellipsoidal" will be recognized as having a specific mathematical definition, describing a particular class of surfaces. It is acknowledged that the surfaces on which the thin walls 11, 12 of the first and second vessel shell portions 15, 16 lie, do not correspond precisely with such a mathematical definition. It is for this reason that the term generally ellipsoidal" has been adopted. However, the herein defined terminology of generally ellipsoidal is believed appropriate as distin guishing the pressure vessel of this invention from the more cylindrical and drum-like structures known and used before this invention. It is to be noted that the configuration ofthe illustrated pressure vessel 10 varies from a true mathematical ellipsoid by the presence of a cylindrical portion, as seen in FIGS. 2 and 4.

In accordance with an important feature of this invention, each of the first and second vessel shell portions 15, 16 defines an open mouth lying generally on a plane dividing the ellipsoid of the pressure vessel 10 on a minor axis thereof. The respective open mouths 17, 18 are indicated in FIGS. 5 and 6. As illustrated in FIGS. 1 and 4, the open mouths lie generally on a plane 20 which divides the ellipsoid of the vessel 10 on a minor axis thereof. As herein used, the phrase minor axis refers to an axis of the surface which is less than the greatest axis through the surface. An additional characteristic of a minor axis" is that a plane on that axis describes with the ellipsoidal surface a plane figure other than a circle and which has a major dimension less than the major dimension of the ellipsoid.

As will be understood, the first and second vessel shell portions 15, 16 may be separated for transportion, in that each of the vessel shell portions may be mounted on a trailer for highway transport or a railway car for rail transport with the open mouth thereof directed downwardly. As so mounted, the height which must be accommodated amounts to little more than one-half the diameter of the largest toroidal tire carcass receivable within the pressure vessel 10. By way of contrast, prior art pressure vessels when so mounted for shipment have risen to a height greater than the diameter of the largest toroidal tire carcass which can be accommodated.

In accordance with the present invention, one of the shell portions is supported in use in a fixed position with the open mouth disposed generally in a vertical plane. As illustrated, the first vessel shell portion 15 is supported in a generally horizontal fixed position, with the open mouth 17 thereof disposed generally in a vertical plane. The other shell portion 16 is supported for movement between a closed chamber position (FIGS. 1,2 and 4) and an open chamber position (FIGS. 5 and 6). In the closed chamber position, the mouths 17, 18 of the shell portions 15, 16 abut and the shell portions cooperate in forming a sealed pressure vessel. In the open chamber position, the mouth 18 of the other shell t portion 16 is withdrawn from the mouth 17 of the one shell portion so as to accommodate the insertion and removal of a toroidal tire carcass 21 into and from the pressure vessel 10.

In accordance with this invention, the movement of the other shell portion 16 between the closed and open chamber positions is pivotal movement relative to the one shell portion 15, accommodated by a pivot means generally indicated at 22 (FIGS. 1, 5 and 6) which operatively interconnects the shell portions. In particular, the pivot means includes a plurality of hook members 24 welded or otherwise fixedly secured to the other shell portion 16 and at least one vertical pivot pin 25 generally aligned with the vertical plane of the mouths 17, I8 and penetrating the hook members 24 and rib members 26 welded or otherwise secured to the one shellportion 15. By the vertical orientation of the at least one pivot pin 25, the other shell portion 16 moves horizontally away from the one shell portion 15 in opening of the pressure vessel to accommodate insertion of a toroidal tire carcass 21.

In order to aid in opening and closing the pressure vessel 10, actuator means generally indicated at 28 are provided which are operatively connected to the shell portions l5, 16 for moving the second shell portion 16 between the closed and open chamber positions. In the form illustrated, the actuator means comprises a pair of pressure cylinder devices 29, such as air or hydraulic cylinders. Each of the cylinders 29 has one end thereof pivotally connected with an appropriate bracket 30 welded or otherwise secured to the first shell portion 15. Further, each of the cylinders 29 has a piston rod 31 (FIG. 1) pivotally connected with an appropriate bracket 32 welded or otherwise secured to the second shell portion 16. By extension and retraction of the piston rod 31 relative to the cylinder 29, in a known manner, forces are exerted between the brackets 30, 32 which move the second shell portion 16 between the open and closed chamber positions.

As pointed out hereinabove, the first shell portion 15 is supported in a fixed position. In the form illustrated, this fixed mounting is accomplished by fixed mounting means comprising a plurality ofleg members 34, 35, 36 (FIGS. 2 and 4) depending from the one shell portion 15 for supporting the one shell portion in a generally horizontal position.

In order to support the second shell portion 16 in the generally horizontal position while accommodating the movement thereof, movable mounting means is provided by a plurality of rollers 38, 39, 40 (FIGS. 1, 2 and 4). The rollers underlie the other shell portion 16 for supporting the same and preferably engage and ride on arcuate smooth tracks 41,42, 43 provided by steel plates mounted on the floor surface underlying the pressure vessel 10.

In using the pressure vessel of this invention, it is desirable to have a toroidal object such as the tire carcass 21 received therewithin supported in a particular predetermined manner during the subjection thereof to elevated temperatures and pressures. More particularly, a relaxed condition of the tire carcass 21 during curing is facilitated by support thereof on a platform means generally indicated at 45 and disposed within the shell portions 15, 16. Desirably, the platform means 45 is divided into two portions. one of which is fixedly mounted within each of the shell portions 15, I6. Undesirable tumbling or free release of the tire carcass 21 during opening and closing of the pressure vessel 10 is avoided by an unequal division of the platform means between the two shell portions l5, 16. That is, the fixed shell portion 15 includes a portion of the platform means 45 which projects into the movable shell portion 16. By such division of the platform means 45, loading of the tire carcass such as the carcass 21 into the first shell portion 15, such as by a fork lift is facilitated.

In use. the pressure vessel 10 must be sealed against pressure loss and locked in sealed relation for purposes of safety. Accordingly, lock means generally indicated at 46 are mounted on one of the shell portions for slectively engaging the other shell portion and for securing the shell portions in closed chamber position. The lock means comprises a plurality of hook members 48 each mounted on the first shell portion 15 for pivotal move ment between a withdrawn position (FIG. 3) and a locking position (FIG. 4). Control over the position of the hook members 48 is exercised by a corresponding plurality of pressure fluid cylinder devices 49, each of which is operatively connected. through a control valve 50, with an appropriate source of pressurizing fluid such as a pump 51. By the application of pressure fluid from the pump 51 through the valve the cylinder devices 49 are actuated to pivot the hook members 48 from the withdrawn position of FIG. 3 to the locking position of FIG. 4 infwhich the hook members engage a flange member at the open mouth 17 of the second shell portion 16. Desirably, an electrical interlock is provided by at least one electrical switch 52 (FIG. 3) positioned to be responsive to movement of at least one hook member 48 between the withdrawn and the locking positions. By appropriate interconnections, the electrical switch 52 precludes pressurization of the pressure vessel for so long as the same remains unlocked. Sealing of the locked pressure vessel is accomplished by a gasket member 54 (FIG. 3).

In the drawings and specification, there has been set forth a preferred embodiment of the invention; and although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation.

That which is claimed is:

1. A generally ellipsoidal pressure vessel adapted to facilitate transport and erection and comprising:

first and second vessel shell portions each having a thin wall lying generally along the surface of onehalfof an ellipsoid of revolution of an ellipse about its minor axis, the halves being formed by the division of the ellipsoid by a plane which includes said minor axis, each of said shell portions having an open mouth defined by said division along said axis,

fixed mounting means for supporting one of said shell portions in a fixed position, and

movable mounting means for supporting the other of said shell portions for movement between a closed chamber position in which said mouths abut and said shell portions cooperate in forming a sealed pressure vessel and an open chamber position in which said mouth of said other shell portion is withdrawn from said mouth of said one shell portion for insertion and removal of a toroidal object into and from said pressure vessel,

said shell portions being separable one from another for transport and erection so as to minimize the bulk of the pressure vessel during transport while maximizing the dimensions of toroidal objects receivable therewithin.

2. A pressure vessel according to claim 1 further comprising pivot means for operatively interconnecting said shell portions for pivotal movement of said other shell portion between said closed and open chamber positions.

3. A pressure vessel according to claim 2 wherein said one shell portion is supported with said open mouth thereof disposed generally in a vertical plane and said pivot means comprises at least one vertical pivot pin generally aligned with said vertical plane of said mouths and spaced from said walls of said shell portions for facilitating adaptation of said pressure vessel to insertion and removal of toroidal objects.

4. A pressure vessel according to claim 2 further comprising actuator means operatively connected with said shell portions for moving said other shell portion from one of said positions to the other.

5. A pressure vessel according to claim 1 wherein said fixed mounting means comprises a plurality of leg members depending from said one shell portion for supporting said one shell portion in a generally horizontal position.

6. A pressure vessel according to claim 5 wherein said movable mounting means comprises a plurality of rollers underlying said other shell portion for supporting said other shell portion in a generally horizontal p0 sition throughout the range of movement thereofv 7. A pressure vessel according to claim 1 further comprising platform means disposed within said shell portions for receiving and supporting toroidal objects placed therewithin.

8. A pressure vessel according to claim 1 further comprising lock means mounted on one of said shell portions for selectively engaging the other of said shell portions and for securing said shell portions in said closed chamber position.

9. A pressure vessel according to claim 8 wherein said lock means comprises a plurality of hook members mounted on said one shell portion which is fixedly mounted.

10. A generally ellipsoidal pressure vessel for receiving tire carcasses to be cured at elevated temperatures and pressures and comprising:

first and second vessel shell portions each having a thin wall lying generally along the surface of onc half of an ellipsoid of revolution of an ellipse about its minor axis, the halves being formed by the division of the ellipsoid by a plane which includes said minor axis, each of said shell portions having an open mouth defined by said division along said plane,

fixed mounting means for supporting one of said shell portions in a generally horizontal position with said open mouth thereof disposed generally in a vertical plane,

movable mounting means for supporting the other of said shell portions for movement between a closed chamber position in which said mouths abut and said shell portions cooperate in forming a sealed pressure vessel and an open chamber position in which said mouth of said other shell portion is withdrawn from said mouth of said one shell portion for insertion and removal of a tire carcass into and from said pressure vessel, and

pivot means for operatively interconnecting said shell portions for pivotal movement of said other shell portion about a vertical pivot axis generally aligned with said vertical plane of said mouths and spaced horizontally from said walls of said shell portions, said mounting means and said pivot means cooperating for facilitating accommodation in a horizontal attitude of a tire carcass to be disposed wthin the pressure vessel while minimizing the height of the 

1. A GENERALLY ELLIPSOIDAL PRESSURE VESSEL ADAPTED TO FACILITATE TRANSPORT AND ERECTION AND COMPRISING: FIRST AND SECOND VESSEL SHELL PORTIONS EACH HAVING A THIN WALL LYING GENERALLY ALONG THE SURFACE OF ONE-HALF OF AN ELLIPSOID OF REVOLUTION OF AN ELLIPSE ABOUT ITS MINOR AXIS, BY A HALVES BEING FORMED BY THE DIVISION OF LTHE ELLIPSOID BY A PLANE WHICH INCLUDES SAID MINOR AXIS, EACH OF SAID SHELL PORTIONS HAVING AN OPEN MOUTH DEFINED BY SAID DIVISION ALONG SAID AXIS, FIXES MOUNTING MEANS FOR SUPPORTING ONE OF SAID SHELL PORTIONS IN A FIXED POSITION, AND MOVABLE MOUNTING MEANS FOR SUPPORTING THE OTHER OF SAID SHELL PORTIONS FOR MOVEMENT BETWEEN A CLOSE CHAMBER POSITION IN WHICH SAID MOUTHS ABUT AND SAID SHELL PORTIONS COOPERATIVE FORMING A SEALED PRESSURE VESSEL AND AN OPEN
 2. A pressure vessel according to claim 1 further comprising pivot means for operatively interconnecting said shell portions for pivotal movement of said other shell portion between said closed and open chamber positions.
 3. A pressure vessel according to claim 2 wherein said one shell portion is supported with said open mouth thereof disposed generally in a vertical plane and said pivot means comprises at least one vertical pivot pin generally aligned with said vertical plane of said mouths and spaced from said walls of said shell portions for facilitating adaptation of said pressure vessel to insertion and removal of toroidal objects.
 4. A pressure vessel according to claim 2 further comprising actuator means operatively connected with said shell portions for moving said other shell portion from one of said positions to the other.
 5. A pressure vessel according to claim 1 wherein said fixed mounting means comprises a plurality of leg members depending from said one shell portion for supporting said one shell portion in a generally horizontal position.
 6. A pressure vessel according to claim 5 wherein said movable mounting means comprises a plurality of rollers underlying said other shell portion for supporting said other shell portion in a generally horizontal position throughout the range of movement thereof.
 7. A pressure vessel according to claim 1 further comprising platform means disposed within said shell portions for receiving and supporting toroidal objects placed therewithin.
 8. A pressure vessel according to claim 1 further comprising lock means mounted on one of said shell portions for selectively engaging the other of said shell portions and for securing said shell portions in said closed chamber position.
 9. A pressure vessel according to claim 8 wherein said lock means comprises a plurality of hook members mounted on said one shell portion which is fixedly mounted.
 10. A generally ellipsoidal pressure vessel for receiving tire carcasses to be cured at elevated temperatures and pressures and comprising: first and second vessel shell portions each having a thin wall lying generally along the surface of one-half of an ellipsoid of revolution of an ellipse about its minor axis, the halves being formed by the division of the ellipsoid by a plane which includes said minor axis, each of said shell portions having an open mouth defined by said division along said plane, fixed mounting means for supporting one of said shell portions in a generally horizontal position with said open mouth thereof disposed generally in a vertical plane, movable mounting means for supporting the other of said shell portions for movement between a closed chamber position in which said mouths abut and said shell portions cooperate in forming a sealed pressure vessel and an open chamber position in which said mouth of said other shell portion is withdrawn from said mouth of said one shell portion for insertion and removal of a tire carcass into and from said pressure vessel, and pivot means for operatively interconnecting said shell portions for pivotal movement of said other shell portion about a vertical pivot axis generally aligned with said vertical plane of said mouths and spaced horizontally from said walls of said shell portions, said mounting means and said pivot means cooperating for facilitating accommodation in a horizontal attitude of a tire carcass to be disposed wthin the pressure vessel while minimizing the height of the vessel. 